The purpose of this project is to provide reference information on anaerobic bacteriology; to characterize the anaerobic bacterial flora of man and animals in disease and health. Primary emphasis is on the clinical infections with anaerobes and on the normal flora of the human, development of improved cultural and differential techniques and procedures, antibiotic susceptibility testing, characterization and pathogenicity of anaerobes and metabolic activities of the organisms, and determination of their incidence and significance in infections or in the normal flora. Original isolates and referred cultures are compared with the characteristics and catalogued collection of approximately 12,000 stains. Genetic homology, cellular composition, nutritional requirements, toxin production and other descriptive information is made available through the reference publication of the laboratory (Anaerobe Laboratory Manual) and specific research articles. Next year we will continue work on DNA/DNA homology of non- sporeforming pathogens, differential phenotypic tests of the clinically significant anaerobes as compared with similar but non-pathogenic types, clinical infections (sinusitis, osteomyelitis), cooperative research with clinical labs on referred material, antibiotic resistance, the intestinal flora and factors of affecting its composition, and description of new species of clinical significance.